The invention relates to new guanidine and amidine derivatives of general formula I 
and the pharmaceutically acceptable salts thereof, processes for preparing them and pharmaceutical compositions containing these compounds. The compounds are valuable neurokinin (tachykinin) antagonists.
The abbreviations used in this specification and claims are explained as follows:
Boc=t-butyloxycarbonyl
DC=thin layer chromatogram
DMF=dimethylformamide
EE=ethyl acetate
FAB-MS=fast atom bombardment mass spectroscopy
RT=room temperature
TBTU=O-benzotriazolyl-tetramethyluronium tetrafluoroborate
TEA=triethylamine
THF=tetrahydrofuran
A simplified format is used for the formulae. In the representations of compounds, all CH3 substituents are indicated by a hyphen, e.g. 
denotes 
The invention relates to new guanidine and amidine derivatives of general formula I 
or the pharmaceutically acceptable salts thereof, wherein
X denotes Nxe2x80x94R3 or CHxe2x80x94R4, wherein R3 denotes R3 
xe2x80x83wherein R5, R6 and R7 independently of one another denote H, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, alkanoyl, benzoyl, heteroaryl, dialkylamino, dialkylaminoalkyl, trialkylammoniumalkyl, cyano, alkyloxycarbonyl, aralkyloxycarbonyl, OH, O-alkyl or O-aryl, wherein the alkyl groups contain 1 to 5 carbon atoms, the cycloalkyl groups contain 3 to 6 carbon atoms, the alkenyl groups contain 2 to 5 carbon atoms, aryl denotes phenyl, or phenyl or naphthyl substituted by methyl or halogen (F, Cl, Br, I);
or R5 and R6 or R6 and R7 together form the group (CH2)2xe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94(CH2)4xe2x80x94, xe2x80x94(CH2)5xe2x80x94 or xe2x80x94(CH2)2 O(CH2)2;
or R3 denotes 
xe2x80x83and R4 denotes 
xe2x80x83wherein R5 to R7 are as hereinbefore defined and
R8=H, alkyl with 1 to 5 carbon atoms or cycloalkyl with 3 to 6 carbon atoms or
R7+R8 together form the group xe2x80x94(CH2)2xe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94(CH2)4xe2x80x94, xe2x80x94(CH2)5xe2x80x94 or xe2x80x94(CH2)2O(CH2)2xe2x80x94;
or R4 denotes 
xe2x80x83wherein R5 is as hereinbefore defined;
Y denotes CH2 or (CH2)2;
Z denotes O or H2;
Ar denotes unsubstituted or mono- to 5-substituted phenyl, or unsubstituted or mono- or disubstituted naphthyl [wherein the substituents of the phenyl and naphthyl independently of one another denote halogen (F, Cl, Br, I), OH, (C1-4)alkyl, Oxe2x80x94(C1-4)alkyl, CF3, OCF3 or NR9R10 (wherein R9 and R10 independently of one another denote H, methyl or acetyl)] or Ar is phenyl substituted by xe2x80x94OCH2Oxe2x80x94 or xe2x80x94O(CH2)2Oxe2x80x94;
R1 denotes phenyl(C1-4)alkyl or phenyl(C1-4)alkanoyl or naphthyl(C1-4)alkyl or naphthylacetyl, wherein phenyl may be substituted by 1 to 3 substituents, wherein the substituents independently of one another denote halogen (F, Cl, Br, I), (C1-4)alkyl, Oxe2x80x94(C1-4)alkyl, CF3, OCF3 or NR19R20 (wherein R19 and R20 independently of one another denote H, methyl or acetyl); and
R2 denotes H, (C1-4)alkyl, (C3-6)cycloalkyl, CH2COOH, xe2x80x94CH2C(O)NH2, OH or phenyl(C1-4)alkyl.
The compounds according to the invention are valuable neurokinin (tachykinin) antagonists which have both substance P antagonism and also neurokinin-A- or neurokinin-B-antagonistic properties. They are useful for the treatment and prevention of neurokinin-mediated diseases.
Compounds of general formula I may contain acid groups, mainly carboxyl groups, and/or basic groups such as amino functions, for example. Compounds of general formula I may therefore occur as internal salts, salts with pharmaceutically acceptable inorganic acids such as hydrochloric acid, sulphuric acid, phosphoric acid, sulphonic acid or organic acids (such as, for example, maleic acid, fumaric acid, citric acid, tartaric acid or acetic acid) or as salts with pharmaceutically acceptable bases such as alkali metal or alkaline earth metal hydroxides or carbonates, zinc or ammonium hydroxides or organic amines such as e.g. diethylamine, triethylamine, triethanolamine, etc.
The compounds according to the invention may occur as racemates, but may also be obtained as pure enantiomers, i.e. in the (R) or (S) form. Compounds which occur as racemates or in the (S) form are preferred.
Results of investigations into the compound according to the invention: The receptor affinity for the NK1 receptor (substance P receptor) is determined on human lymphoblastoma cells (IM-9) with cloned NK1 receptors, by measuring the displacement of 125I-labelled substance P. The Ki values thus obtained show the efficacy of the compounds.
The compounds according to the invention are valuable neurokinin (tachykinin) antagonists which have both substance P antagonism and also neurokinin-A- or neurokinin-B-antagonistic properties. They are useful for the treatment and prevention of neurokinin-mediated diseases:
For preventing or treating inflammatory or allergic diseases
of the respiratory tract such as asthma, chronic bronchitis, hyperreactive respiratory tract, emphysema, rhinitis, cough,
of the eyes, such as conjunctivitis and iritis,
of the skin, such as dermatitis in contact eczema, urticaria, psoriasis, sunburn, insect bites, itching, sensitive or hypersensitive skin,
of the gastro-intestinal tract such as gastric and duodenal ulcers, ulcerative colitis, Crohn""s disease, irritable bowel, Hirschsprung""s disease,
of the joints, such as rheumatoid arthritis, reactive arthritis and Reiter syndrome; for treating diseases of the central nervous system, such as dementia, Alzheimer""s disease, schizophrenia, psychoses, depression, headache (e.g. migraine or tension headaches), epilepsy; Parkinson""s disease, stroke,
for treating Herpes zoster and postherpetic pain, tumours, collagenoses, dysfunction of the urinary tract, haemorrhoids, nausea and vomiting, triggered by radiation or cytostatic therapy, for example, or movement and pain of all kinds.
The invention therefore also relates to the use of the compounds according to the invention as curative agents and pharmaceutical preparations which contain these compounds. They are preferably used in humans. The compounds according to the invention may be administered by intravenous, subcutaneous, intramuscular, intraperitoneal or intranasal route, by inhalation, by transdermal route, if desired with the aid of iontophoresis or enhancers known from the literature, and by oral route.
For parenteral administration the compounds of formula I or the physiologically acceptable salts thereof are brought into solution, suspension or emulsion, optionally with the substances conventionally used for this, such as solubilisers, emulsifiers or other adjuvants. Suitable solvents include, for example: water, physiological saline solutions or alcohols, e.g. ethanol, propandiol or glycerol, sugar solutions such as glucose or mannitol solutions or a mixture of different solvents.
Moreover, the compounds may be administered by means of implants, e.g. of polylactide, polyglycolide or polyhydroxybutyric acid or intranasal preparations. Preferred compounds of general formula 1 are those wherein
X denotes Nxe2x80x94R3 or CHxe2x80x94R4, wherein
R3 denotes 
xe2x80x83wherein R5, R6 and R7 independently of one another denote H, alkyl, cycloalkyl, aryl, aralkyl, alkanoyl, benzoyl, dialkylamino, dialkylaminoalkyl, trialkylammoniumalkyl, cyano, alkyloxycarbonyl, aralkyloxycarbonyl, OH, O-alkyl or O-aryl,
wherein the alkyl groups contain 1 to 4 carbon atoms, the cycloalkyl groups contain 3 to 6 carbon atoms, aryl denotes phenyl or phenyl substituted by methyl or halogen (F, Cl, Br, I);
or R5 and R6 or R6 and R7 together form the group xe2x80x94(CH2)2xe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94(CH2)4xe2x80x94, xe2x80x94(CH2)5xe2x80x94 or xe2x80x94(CH2)2 O(CH2)2;
or R3 is 
xe2x80x83and R4 is 
xe2x80x83wherein R5 to R7 are as hereinbefore defined and
R8=H, alkyl with 1 to 5 carbon atoms or cycloalkyl with 3 to 6 carbon atoms or
R7+R8 together form the group xe2x80x94(CH2)2xe2x80x94, xe2x80x94(CH2)3xe2x80x94, xe2x80x94(CH2)4xe2x80x94, xe2x80x94(CH2)5xe2x80x94 or xe2x80x94(CH2)2 O(CH2)2xe2x80x94;
Y denotes CH2 or (CH2)2;
Z denotes O or H2;
Ar denotes unsubstituted or mono- to 5-substituted phenyl [wherein the substituents of the phenyl independently of one another denote halogen (F, Cl, Br, I), OH, (C1xe2x88x92C)alkyl, Oxe2x80x94(C1-4)alkyl, CF3, OCF3 or NR9R10 (wherein R9 and R10 independently of one another denote H, methyl or acetyl)] or Ar is phenyl substituted by xe2x80x94OCH2Oxe2x80x94 or xe2x80x94O(CH2)2Oxe2x80x94;
R1 denotes phenyl(C1-C4)alkyl or phenyl(C1-C4)alkanoyl, wherein phenyl may be substituted by 1 to 3 substituents, wherein the substituents independently of one another denote halogen (F, Cl, Br, I), (C1-4)alkyl, Oxe2x80x94(C1-4)alkyl, CF3, OCF3 or NR19R20 (wherein R19 and R20 independently of one another denote H, methyl or acetyl); and
R2 denotes H, (C1-4)alkyl or (C3-6)cycloalkyl.
Particularly preferred are those compounds wherein
X denotes Nxe2x80x94R3 or CHxe2x80x94R4, wherein
R3 denotes 
and R4 denotes 
and R5 to R8, Z, Ar, R1 and R2 are as hereinbefore defined, and Y denotes CH2.
Of these compounds, the preferred ones are those wherein Z is oxo, and/or Ar is unsubstituted phenyl, particularly those wherein Ar is phenyl mono- or disubstituted by halogen, preferably Ar is dichlorophenyl; and/or wherein R1 denotes substituted phenylacetyl (preferably 3,4-di-trifluoromethylphenyl-acetyl) or wherein R1 is substituted phenylethyl, wherein the phenyl is substituted by 2 substituents which, independently of one another, denote halogen (F, Cl, Br, I), (C1-4)alkyl or CF3, particularly wherein the substituents of the phenyl are CF3 CH3 or F, (preferably wherein the two substituents of the phenyl are CF3); and/or wherein R2 is (C1-4)alkyl, preferably wherein R2 is methyl.
Compounds of formula I are preferred wherein the group 
is 
One aspect of the invention relates to compounds of formula I wherein X denotes the group CR4, wherein
R4 is 
wherein
R5, R6, R7 and R8 independently of one another denote H, alkyl with 1 to 4 carbon atoms or cycloalkyl with 3 to 6 carbon atoms; or
R7 and R8 together form the group (CH2)2, (CH2)3, (CH2)4 or (CH2)5. Compounds wherein R5 and R6 denote H and R7 and R8 together form the group (CH2)2 or those wherein R5 and R6 denote H and R7 and R8 are cyclohexyl are preferred.
Another important aspect of the invention relates to compounds of formula I wherein X is the group NR3 
wherein
R3 is 
wherein
R5 and R6 independently of one another denote H, alkyl with 1 to 4 carbon atoms, cycloalkyl with 3 to 6 carbon atoms, phenyl, or phenyl, benzyl or benzoyl substituted by methyl or halogen (F, Cl, Br, I), CN, alkyloxycarbonyl (wherein the alkyl group contains 1 to 4 carbon atoms), benzyloxycarbonyl, alkoxy with 1 to 4 carbon atoms or dialkylamine (wherein the alkyl groups contain 1 to 4 carbon atoms),
R7 denotes H or alkyl with 1 to 4 carbon atoms; or R5 and R6 or R6 and R7 together form the group (CH2)2, (CH2)3, (CH2)4 or (CH2)5; or R6 and R7 together form the group xe2x80x94(CH)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94.
Of these compounds, the preferred ones are those wherein
a) R5 and R6 independently of one another denote H, alkyl with 1 to 4 carbon atoms, cycloalkyl with 3 to 6 carbon atoms, phenyl, phenyl, benzyl or benzoyl substituted by methyl or halogen (F, Cl, Br, I);
R7 is H or alkyl with 1 to 4 carbon atoms or
R5 and R6 or R6 and R7 together form the group (CH2)2, (CH2)3, (CH2)4 or (CH2)5; or R6 and R7 together form the group xe2x80x94(CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94;
b) R5 and R6 independently of one another denote H, alkyl with 1 to 4 carbon atoms, cyclohexyl, phenyl, methyl-substituted phenyl, benzyl or benzoyl;
R7 is H or methyl; or
R5 and R6 together form the group (CH2)2 or R6 and
R7 together form the group (CH2)5 or xe2x80x94(CH)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94;
c) R5-denotes H, alkyl with 1 to 4 carbon atoms, cyclohexyl, methyl-substituted phenyl, benzyl or benzoyl;
R6 denotes H, alkyl with 1 to 3 carbon atoms, cyclohexyl, phenyl, methyl-substituted phenyl or benzyl;
R7 is H or methyl; or
R5 and R6 together form the group xe2x80x94(CH2)2xe2x80x94 or R6 and R7 together form the group (CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94;
d) R5 and R6 independently of one another denote H, CH3, CH(CH3)2, phenyl or benzyl, R7 is H or CH3, or
R5 and R6 together form the group xe2x80x94CH2CH2xe2x80x94 or R6 and R7 together form the group xe2x80x94(CH2)2xe2x80x94Oxe2x80x94(CH2)2xe2x80x94.
Particularly preferred are compounds of general formula I, wherein X denotes the group 
The following compounds are particularly preferred: 
The compounds may be prepared by methods known per se. Advantageous methods are shown and described in the diagrams which follow.
The compounds of general formula 
wherein
X denotes Nxe2x80x94R3, wherein R3 is 
may be prepared by reacting a compound of general formula I wherein R3 denotes hydrogen with the corresponding amino-iminomethanesulphonic acid, the corresponding carbodiimide or thiourea. This process is illustrated by methods A to C for pounds wherein Y is CH2, Ar is phenyl, Z is oxo, R1 is difluorophenylethyl and R2 is methyl. However, the process can be used analogously for all compounds of formula I wherein X is NR3.
Diagram 1 (Method A) 
Method A
Piperazine having a protecting group in the 1 position is reacted with 2-halophenyl-acetate to obtain N-protected piperazinyl-phenylacetate. This is saponified under suitable conditions, e.g. with sodium hydroxide solution, to obtain the corresponding carboxylic acid. This is then linked to an amine according to the invention, e.g. N-methyl-3,5-bis-trifluoromethylphenethyl-amine, using a suitable coupling reagent such as TBTU. In the next step the protecting group is cleaved from the piperazine part of the molecule using a suitable cleaving reagent. In the last step of the reaction, the free piperazine-N is reacted with unsubstituted or substituted amino-iminomethanesulphonic acid (which is obtained for example by oxidation of the corresponding thiourea using H2O2) to obtain the desired guanidine. Compounds of the type in Examples 1-3 may advantageously be prepared by method A, for example.
Diagram 2 (Method B) 
Method B
The same procedure is used as in method A, except that in the last step, the reaction is carried out with carbodiimides instead of the substituted methanesulphonic acid. These may be either N,Nxe2x80x2-disubstituted carbodiimides or N,N,Nxe2x80x2-trisubstituted carbodiimides, which are then used in the form of a salt, e.g. the iodide.
The compounds of the type in Examples 4 to 7 may advantageously be prepared according to method B, for example.
Diagram 3 (Method C) 
Method C
The same procedure is used as in method A, except that in the last step, instead of the substituted methanesulphonic acid, a substituted thiourea is reacted together with HgO.
Compounds of the type in Example 9 may advantageously be prepared according to method C, for example.
The compound of general formula 
may also be prepared by reacting the corresponding piperazine derivative or piperidine derivative with the corresponding amide. This process is illustrated by method D and analogous method E for compounds wherein Y denotes CH2, Ar is phenyl, Z is oxo, R1 is difluorophenylethyl and R2 is methyl. The process may be used analogously, however, for all compounds of formula I wherein X is NR3 or CR4. Particularly preferred are compounds wherein
R3 denotes 
or
R4 denotes 
The reaction is carried out in an inert solvent in the presence of a base.
Diagram 4 (Method D) 
Method D
Analogously to the last step in method A, first of all, piperazine protected in the 1 position is reacted with unsubstituted or substituted amino-iminomethanesulphonic acid. Other substituents may be introduced into the resulting guanidine by alkylation or acylation if required. In the next step the piperazine derivative is obtained with an unsubstituted piperazine-N by cleaving the protecting group with a cleaving reagent.
The reactant for this piperazine derivative is obtained as shown on the right in Diagram 4. (R)-Mandelic acid is reacted with methanesulphonic acid halide to obtain the (R)-2-(methanesulphonyloxy)-acetic acid. This is then reacted with a coupling reagent and the correspondingly substituted phenethylamine to form the corresponding amide, or it is converted into the corresponding acid halide (e.g. with SOCl2/SO2Cl2) and then converted, with the suitably substituted phenethylamine, into the corresponding amide. In the last step the amide thus obtained is reacted with the piperazine derivative described above, whereupon a Cxe2x80x94N bond is formed, with elimination of methanesulphonate, whilst at the same time the chiral centre is reversed. The reaction is carried out in an inert solvent such as e.g. DMF or acetonitrile in the presence of a base such as TEA or N-methylmorpholine, for example, at temperatures between 20xc2x0 C. and 120xc2x0 C. The reaction time is between 0.5 h and 48 h.
Compounds of the type in Example 8 may advantageously be synthesised according to method D. 
The method is carried out analogously to method D. Compounds of the type in Example 36 may advantageously be synthesised according to Method E.